<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: ZendServer.php 23775 2011-03-01 17:25:24Z ralph $
 */

/** @see Zend_Cache_Backend_Interface */
require_once 'Zend/Cache/Backend/Interface.php';

/** @see Zend_Cache_Backend */
require_once 'Zend/Cache/Backend.php';

/**
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Backend
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_Cache_Backend_ZendServer extends Zend_Cache_Backend implements Zend_Cache_Backend_Interface {
	/**
	 * Available options
	 *
	 * =====> (string) namespace :
	 * Namespace to be used for chaching operations
	 *
	 * @var array available options
	 */
	protected $_options = array ('namespace' => 'zendframework' );
	
	/**
	 * Store data
	 *
	 * @param mixed  $data        Object to store
	 * @param string $id          Cache id
	 * @param int    $timeToLive  Time to live in seconds
	 * @throws Zend_Cache_Exception
	 */
	abstract protected function _store($data, $id, $timeToLive);
	
	/**
	 * Fetch data
	 *
	 * @param string $id          Cache id
	 * @throws Zend_Cache_Exception
	 */
	abstract protected function _fetch($id);
	
	/**
	 * Unset data
	 *
	 * @param string $id          Cache id
	 */
	abstract protected function _unset($id);
	
	/**
	 * Clear cache
	 */
	abstract protected function _clear();
	
	/**
	 * Test if a cache is available for the given id and (if yes) return it (false else)
	 *
	 * @param  string  $id                     cache id
	 * @param  boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested
	 * @return string cached datas (or false)
	 */
	public function load($id, $doNotTestCacheValidity = false) {
		$tmp = $this->_fetch ( $id );
		if ($tmp !== null) {
			return $tmp;
		}
		return false;
	}
	
	/**
	 * Test if a cache is available or not (for the given id)
	 *
	 * @param  string $id cache id
	 * @return mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
	 * @throws Zend_Cache_Exception
	 */
	public function test($id) {
		$tmp = $this->_fetch ( 'internal-metadatas---' . $id );
		if ($tmp !== false) {
			if (! is_array ( $tmp ) || ! isset ( $tmp ['mtime'] )) {
				Zend_Cache::throwException ( 'Cache metadata for \'' . $id . '\' id is corrupted' );
			}
			return $tmp ['mtime'];
		}
		return false;
	}
	
	/**
	 * Compute & return the expire time
	 *
	 * @return int expire time (unix timestamp)
	 */
	private function _expireTime($lifetime) {
		if ($lifetime === null) {
			return 9999999999;
		}
		return time () + $lifetime;
	}
	
	/**
	 * Save some string datas into a cache record
	 *
	 * Note : $data is always "string" (serialization is done by the
	 * core not by the backend)
	 *
	 * @param string $data datas to cache
	 * @param string $id cache id
	 * @param array $tags array of strings, the cache record will be tagged by each string entry
	 * @param int $specificLifetime if != false, set a specific lifetime for this cache record (null => infinite lifetime)
	 * @return boolean true if no problem
	 */
	public function save($data, $id, $tags = array(), $specificLifetime = false) {
		$lifetime = $this->getLifetime ( $specificLifetime );
		$metadatas = array ('mtime' => time (), 'expire' => $this->_expireTime ( $lifetime ) );
		
		if (count ( $tags ) > 0) {
			$this->_log ( 'Zend_Cache_Backend_ZendServer::save() : tags are unsupported by the ZendServer backends' );
		}
		
		return $this->_store ( $data, $id, $lifetime ) && $this->_store ( $metadatas, 'internal-metadatas---' . $id, $lifetime );
	}
	
	/**
	 * Remove a cache record
	 *
	 * @param  string $id cache id
	 * @return boolean true if no problem
	 */
	public function remove($id) {
		$result1 = $this->_unset ( $id );
		$result2 = $this->_unset ( 'internal-metadatas---' . $id );
		
		return $result1 && $result2;
	}
	
	/**
	 * Clean some cache records
	 *
	 * Available modes are :
	 * 'all' (default)  => remove all cache entries ($tags is not used)
	 * 'old'            => unsupported
	 * 'matchingTag'    => unsupported
	 * 'notMatchingTag' => unsupported
	 * 'matchingAnyTag' => unsupported
	 *
	 * @param  string $mode clean mode
	 * @param  array  $tags array of tags
	 * @throws Zend_Cache_Exception
	 * @return boolean true if no problem
	 */
	public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array()) {
		switch ($mode) {
			case Zend_Cache::CLEANING_MODE_ALL :
				$this->_clear ();
				return true;
				break;
			case Zend_Cache::CLEANING_MODE_OLD :
				$this->_log ( "Zend_Cache_Backend_ZendServer::clean() : CLEANING_MODE_OLD is unsupported by the Zend Server backends." );
				break;
			case Zend_Cache::CLEANING_MODE_MATCHING_TAG :
			case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG :
			case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG :
				$this->_clear ();
				$this->_log ( 'Zend_Cache_Backend_ZendServer::clean() : tags are unsupported by the Zend Server backends.' );
				break;
			default :
				Zend_Cache::throwException ( 'Invalid mode for clean() method' );
				break;
		}
	}
}
